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F2 Dissolution Calculator
Please provide two sets of dissolution percentages, separated by a semicolon “;”. Each set should contain an equal number of time points. For example: `50, 60, 70, 80; 55, 63, 72, 85`. Click the “Calculate” button to find the F2 similarity factor.
What is the F2 Dissolution Similarity Factor?
The F2 similarity factor is a widely used criterion in pharmaceutical development to compare the dissolution profiles of two drug products (e.g., a test product and a reference product). It provides a quantitative measure of the similarity between two dissolution curves based on the percentage of drug dissolved over time. A higher F2 value indicates greater similarity.
F2 Similarity Factor Formula
The F2 similarity factor is calculated using the following formula:
| F2 = 50 × log { [1 + (1/n) × ∑ (Rt – Tt)2]-0.5 × 100 } |
Where:
- n = the number of time points.
- Rt = the mean percent dissolved of the reference product at time point t.
- Tt = the mean percent dissolved of the test product at time point t.
Conditions for F2 calculation:
- At least 3 time points (excluding t=0).
- The number of dissolution points should be the same for both profiles.
- Only one measurement should be considered after 85% dissolution of the product.
- The variability (Coefficient of Variation) at early time points should not be too high (e.g., CV of not more than 20% at the first time point and 10% at other time points for individual tablet results).
Interpretation of F2 Values
An F2 value between 50 and 100 generally indicates that the two dissolution profiles are similar. A value of 100 means the profiles are identical. Regulatory bodies typically consider an F2 value of 50 or greater to be indicative of similarity, implying that the dissolution performance of the test product is comparable to that of the reference product.
Example Calculation
Let’s calculate the F2 factor for two dissolution profiles:
| EX: |
Reference (R): 50, 60, 70, 80, 90 Test (T): 55, 63, 72, 85, 92 n = 5 time points Differences squared (Rt – Tt)2: (50-55)2 = (-5)2 = 25 (60-63)2 = (-3)2 = 9 (70-72)2 = (-2)2 = 4 (80-85)2 = (-5)2 = 25 (90-92)2 = (-2)2 = 4 Sum of squared differences (∑ (Rt – Tt)2) = 25 + 9 + 4 + 25 + 4 = 67 F2 = 50 × log { [1 + (1/5) × 67]-0.5 × 100 } F2 = 50 × log { [1 + 13.4]-0.5 × 100 } F2 = 50 × log { [14.4]-0.5 × 100 } F2 = 50 × log { [0.2635] × 100 } F2 = 50 × log (26.35) F2 = 50 × 1.4208 F2 ≈ 71.04 Since F2 (71.04) is between 50 and 100, the two dissolution profiles are considered similar. |